The Survival of Stonehenge

Much of Stonehenge has remained almost unchanged since Stone Age builders erected its massive sandstone boulders, or sarsens, 5,000 years ago on England's Salisbury Plain.

A new study reveals how the monument has stood the test of time so successfully: The quartz crystals that make up the sarsens form an interlocking structure that makes the boulders nearly indestructible.

"Now we've got a good idea why this stuff's still standing there," David Nash, a professor of physical geography at the University of Brighton who co-authored the study, told Insider. "The stone is incredibly durable — it's really resistant to erosion and weathering."

The study also revealed that some of Stonehenge's sarsens contain grains of rock that are between 1 billion and 1.6 billion years old.

The new research was born out of an act of repatriation.

In 1958, a team was repairing a cracked chunk of sandstone, and a driller named Robert Phillips took a 3-foot-long piece of Stonehenge. 

He eventually brought the relic to his home in Florida, but after 60 years, the Phillips family repatriated it to English Heritage, a charity that preserves Stonehenge.

The rock's return offered Nash's team an opportunity to investigate the monument's geological origins. Stonehenge is protected by law, so it's impossible to extract new samples for study.  READ MORE